Valve-gear for engines.



0. 1). PARKER.

VALVE GEAR FOR ENGINES.

APPLICATION IILED AUG.1, 1904.

983,564, Patented Feb. 7, 1911 3 SEEETS-SHEET l.

THE NORRIS PETERS ca., wAsnmamu, o. c

O.D.PARKER. VALVE GEAR FOR ENGINE$.

APPLICATION FILED AUG. 1, 1904.

983,564. Patented Feb. 7, 1911.

3 SE BBTS SHEET 2.

wil'rcesses Iw/erC/Ot 0. 1). PARKER. VALVE GEAR FOR ENGINES. APPLICATIONTILED AUG. 1 1904.

Patented Feb. 7, 1911.

3 SHEETS-SHEET 3.

THE Nnmfls PETERS ca. wnsumaron. u. c.

FTCE.

CHARLES D. PARKER, OF WORCESTER, MASSACHUSETTS.

VALVE-GEAR FOR ENGINES.

esasel.

Specification of Letters Patent.

Patented Feb. '7, 1911.

Application filed August 1, 1904. Serial No. 218,956.

To all whom it may concern:

Be it known that I, CHAnLEs D. PARKER, a citizen of the United States,residing at lVoi-cester, in the county of Worcester and State ofMassachusetts, have invented a new and useful Valve-Gear for Engines, ofwhich the following is a specification.-

This invention relates to an arrangement of engine valves and ofconnections for operating the valves.

The especial objects of this invention are to provide simple andeflicient connections for operating the inlet and exhaustvalves of asteam engine in such a way that the valves will have quick opening andclosing movements and dwells or slow movements while in their open orclosed positions; to provide for maintaining two valve-closed passagesbetween the steam-chest and eX- haust during most of the time ofoperation; and to combine the steam and exhaust valves so that an enginewill have very small clearance or dead spaces.

In the accompanying three sheets of drawings, Figure 1 is av side viewof suiiicient parts of a steam engine to illustrate the application ofmy invention thereto. Fig. 2 is a detail view of the connections foroperating one of the inlet valves. Fig. 3 is a side view of the partsshown in Fig. 2. Figs. 4 and 5 are perspective views of the parts shownin Fig. 2. Fig. 6 is a detail view showing a form of operating bar whichmay be used when it is desired to operate the valves by hand. Fig. 7 isa detail view showing the position of the links when the engine cylinderis exhausting. Fig. 8 is a sectional view showing the position of thevalves corresponding to the position of parts shown in Fig. 7. Fig. 9 isa detail view showing the position of the links when the exhaust valvehas closed. Fig 10 is a sectional view showing the valves in positioncorresponding to Fig. 9. Fig. 11 is a detail view showing the positionof the links while the steam valve is opened. Fig. 12 is a sectionalview showing the valves in position corre sponding to Fig. 11. Fig. 13is a detail view showing the parts in the position when the cut-offworks to close the inlet valve, and Fig. 1 1 is a sectional view showingthe valves in position corresponding to Fig. 13.

In the economical operation of steam engines it is essential that boththe inlet and the exhaust valves should open and close promptly, andthat these valves should be given the proper amount of dwell in theiropened or closed positions. That is to say, a prompt operation of thevalves of a steam engine is necessary in order to avoid the wire-drawingor throttling of the steam passages which materially reduces theefficiency of an engine.

A valve gear constructed according to this invention has been especiallydesigned to secure a prompt and reliable operation of the valves bymeans ofconnections operated from a longitudinally movable slide or bar,the valves being operated by links which are so connected to crank-armsthat a crank-arm and its link will be substantially on dead center whena dwell of a valve is desired, and each link will stand at aconsiderable angle to its crank-arm when imparting the desired quickopening or closing movements.

Referring to the drawings and in detail, A designates a cylinder castingwhich is supported on a foundation-plate P. Extending from one end ofthe cylinder casting A is an engine frame F. These parts may be of theusual or ordii'lary construction and need not be completely illustratedherein.

Fitted transversely into the cylinder easting near each end thereof is acasing 10, each containing an outlet valve 11, as shown most clearly inFigs. 8, 10, 12 and 14c; while also fitted transversely into the enginecasting near each end thereof is a valve casing 12 containing a steamvalve 13. The connections for operating each set of valves 11 and 13 ateach end of the cylinder are most clearly illustrated in Fig. 1. Theseconnections comprise an actuated slide or bar 14 which is movedlongitudinally by a hookrod 15 which forms a connection from the slide14: to be operated by an eccentric on the main shaft of the engine inthe ordinary manner.

at each end the sliding bar 14: is connected by a link 16 to a crank arm17 secured upon the valve-stem 18 of an exhaust valve, and at each endalso the slide 14: is connected by a link 19 to a rock-plate 20 which isjournaled upon an extension E extending out from an inlet valve casingas shown in Fig. 3. Pivotally mounted on the rock-plate 20 is a latch 21having a steel contact strip engaging a steel contact strip of arock-plate 22 secured upon the stem of the inlet valve. The latch 21 maymove down into engagement by gravity, or may be pressed down by aspring, if desired. Connected to the rockplate 22 is a link 23 which isconnected at its upper end to a dash-pot rod 24:. These dash-pots may beof the ordinary or usual construction, and need not be herein de scribedat length. In the use of these connections for operating an inlet valveit will be seen that the latch 2-1 serves to open the inlet valve, andthe dash-pot connections serve to close the inlet valve.

Connections for releasing the latch so as to secure a variable closingor cut-oil of the steam valve are most clearly illustrated in Fig. 4. Asshown in this figure, 25 designates a throw-ofi' bell-crank lever whichis pivoted to the rock-plate 22. One arm of the throw-oft lever 25 isadapted to engage the latch 21, while the other arm of the throw-oftlever 25 engages a cam or releasing piece 26. The piece 26, as shown inFig. 1, is connected by a link 27 to a wrist-plate 28, the wrist-plate28 being shifted or turned by a connection 29 from the governor of theengine in the ordinary manner.

Considering now the relation of the parts by means of which I secure thedesired quick opening movements and dwells of the valves, the action ofthe parts is most clearly illustrated in Figs. 7 to 1% inclusive. IVhenthe parts occupy the positions illustrated in F igs.v 7 and 8, it willbe seen that the link 19 is substantially upon a dead center withpractice the crank-arm 17 and link 16 preferably being substantially atright angles at this time) so that a quick closing movementwill beimparted to the exhaust valve 1].. hen the parts occupy the positionsillustrated in Figs. 9 and 10 both the inlet and exhaust valves will beclosed, but the link 19 will stand at a considerable angle to theeffective crank-line 1, and the direction of movement of the link 16will be substantially around a dead center with respect to the crank-arm17 and it follows from this that in passing from the positionsillustrated in Figs. 9 and 10 to the positions illustrated in Figs. 11and 12, a quick opening motion will be imparted to the inlet valve,while the outlet valve will substantially dwell or have comparativelylittle motion imparted thereto. In Figs. 13 and 14: the parts are shownin the same relative positions as in Figs. 11 and 12, except that theinlet valve has been allowed to close by the operation of the automaticcut-oft. In a complete valve gear as thus constructed and operated itwill be seen that by means of direct link connections .trom a sliding orreciprocating bar I am enabled to secure the desired motion of theengine valves in a simple and etlicient manner.

In the construction illustrated, it will be seen that the steam chest isbelow the cylinder and that live steam is introduced into the enginecylinder through the casing of the exhaust valve. This invention is,especially applicable to this type of engine, because in such enginesas heretofore ordinarily constructed, during considerable periods ofeach operation the steam chest will be separated from the exhaust pipesin1- ply by the main shut-off valve, and if this valve does not fitabsolutely tight there will be a direct leakage from the steam chest tothe exhaust, this leakage in some cases frequently increasing on accountof the erosion and wear due to the leaking steam. In an engine equippedwith a valve mechanism according to this invention this diiliculty isovercome to a very large measure for the reason that the opening for thelive steam through the outletvalve-casing may remain open only a part ofthe time of one stroke of the engine-piston, the outlet valve turning toclose this passage with a motion which is very slow at first, but witha. quick final closing action which will intcrpose the two valvesbetween the steam chest and outlet pipe during a considerably greaterperiod of each cycle of operation than has heretofore been possible withthe slow opening outlet valves heretofore used in engines of this type.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent of the United States is:

1. In an engine valve gear, the combination oi an exhaust valve easinghaving an inlet port, an exhaust port, and a cylinder port, anoscillating exhaust valve therein, an oscillating steam valve adjaccntto the exhaust valve and controlling the inlet port to the exhaust valvecasing whereby steam 'is admitted through said exhaust valve to thecylinder of the engine from said inlet port, a movable member, two linksconnecting the movable member with the inlet valve and outlet valve,said links being pivoted to the movable member at adjacent points andextending therefrom at a material angle to each other in all positions,whereby a quick opening action is given to the inlet valve and a quickopening and closing action to the outlet valve and double valve-seatedopenings are maintained the greater partof the time between thesteam-chest and the exhaust.

2. In an engine valve gear, the combination of an exhaust valve casinghaving an inlet port, an exhaust port, and a cylinder port, anoscillating exhaust valve, an oscillating steam valve controlling theinlet port to the exhaust valve casing whereby steam is admitted throughsaid exhaust valve to the cylinder of the engine from said inlet port, asliding bar or plate, a crank-arm and link connection between each ofsaid valves and the sliding bar, the line of motion of one of said linksbeing at a substantial angle to its crank-arm, while the line of motionof the other of said links is substantially on dead center, and a tripmechanism for the steam valve, whereby quick opening and variablecut-off action will be secured for the steamwalve, and quick opening andclosing action for the exhaust valve, whereby during most of the time ofoperation two valve closed-passages will be maintained between the steamchest and exhaust.

3. In avalve gear, the combination of an oscillating inlet valve, anoscillating exhaust valve having ports for admitting steam therethroughto the cylinder from the inlet valve, crank-arms for said valves, amovable bar, and links pivotally connecting said crank-arms with the barat adjacent points and at a substantial angle to each other.

In testimony whereof I have hereunto set my hand, in the presence of twosubscribing I witnesses.

CHAS. D. PARKER.

itnesses LOUIS W'. SOUTHGATE, PHILIP V. Sourrrea'rn.

